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Follow the reluctant adventures in the life of a Welsh astrophysicist sent around the world for some reason, wherein I photograph potatoes and destroy galaxies in the name of science. And don't forget about my website, www.rhysy.net

Wednesday, 27 February 2013

A few days ago I joined the Google+ space community and posted a timeline of the Universe I made a short while back. This proved a popular post, so perhaps it's worth a short overview.

Current thinking is that the Universe stated with a Big Bang about 14 billion years ago. It was very hot, got bigger and then cooled down. Stars formed. Stars became galaxies. Galaxies swirled around and kept crashing into year other. About 5 billion years ago, the solar system formed, though this is a minor detail only of interest to everyone on Earth and probably no-one else in the Universe gives a damn.

So, how do we know that this is true ? Well, some parts we know definitely, some parts are very likely, and others are downright dodgy. Here I'll try to explain which is which. If you want to learn more, click on the links !

1) The Big Bang
Unfortunately, I begin with the statement that the Big Bang is the moment of creation. This is dramatic, but wrong. In fact, the Big Bang theory is about what happened immediately after that still-mysterious moment. Why the Universe decided to give the whole "existence" thing a shot is anyone's guess, so don't let me tell you not to believe that God / the Flying Spaghetti Monster / pure science wasn't responsible. They're all equally likely at this point.

Of course, it's well-known that fundamentalist religious types don't approve of the Big Bang, because the Universe was created when God sneezed sometime in October of 3000 BC, at some point after lunch but before mid-afternoon tea, probably on a Tuesday. Or something. Great*. Yet for a less prominent minority, the Big Bang is far too godly, because it allows room for a an initial divine spark. You just can't win.

*No, not really.
But I digress. The science case that the Universe was once a lot smaller and hotter than it is now is pretty strong, verging on overwhelming. We know that galaxies are all moving apart, so they must have been closer together in the past - that's just common sense. The Big Bang theory predicted the Universe should be filled with background radiaiton, which it is. It also does a pretty good job of explaining the chemical composition of the Universe.

A reassuring point is that the age of the Universe predicted by cosmological models is in agreement with other, independent constraints such as the age of stars. Since dwarf stars are predicted to be able to shine for trillions of years, we really ought to see such old stars if any existed. That we don't see any is a pretty good indicator that the Universe hasn't been around forever.

A final point here is that we're quite sure the Universe really is expanding, and it isn't that all the galaxies just happen to be rushing away from us, as though we were at the center of an explosion (that link has an excellent hands-on project for those who are really interested). Apart from the constraints of cosmological models, geometrical considerations also support this, and the Tolman test proves independently of all this that the expansion is real.

The Big Bang theory is not without problems - but the basic view of a small, hot Universe expanding into the one we see today is pretty sound.

2) InflationKABOOOOM !
That is the sound the Big Bang did not make around 14 billion years ago, because it wasn't an explosion in the conventional sense. What it was was a load of really hot material rushing apart at tremendous speed, which amounts to the same thing in many ways.

Explosions are messy. That much is just true. So it seems quite reasonable to expect that the Big Bang would also have been messy, even if it wasn't your typical exploding barrel of gunpowder. The big problem is that Universe we see today is just too damn boring. Or, to be more accurate, it's the same everywhere. Nothing but galaxies, galaxies, and more galaxies, wherever we look. YAWN.

In the immortal words of Bart Simpson..."Wow ! The Universe is so BORING !"

Seriously though, why is it so uniform ? How come we don't see huge parts of it filled with nothing but sheep* or old socks ? In fact, there's quite a lot of structure, but there's nothing that can't be explained by the simple action of gravity.

* Not counting some parts of Wales.

BAAA !

I exaggerated the bit about sheep, of course. The point is the structures produced in the expanding fireball of the Big Bang shouldn't look like structures only produced by gravity - so where are they ? Inflation gets around this tricky problem by saying that the very early Universe expanded very very very rapidly. This means that everything we can see is actually just a minute part of a single, much greater structure. The messiness is there - it's just much bigger than anything we can ever see.

And that's great, except that no-one knows what caused it.

Should that be worrying ? Well, yes, probably. Nonetheless, the evidence for a small, hot early Universe seems too strong for this to be a real concern. We know basically what happened, just not how or why. It's like having a confession from a murderer who doesn't give a reason - and the Universe is bloody complicated, so it doesn't seem at all unreasonable to me that it's going to take a long time to solve, if we ever do.

3) Galaxy EvolutionHAHAHAH !
I laugh because this is what I work on, and I'm only too aware of how controversial the whole thing is. But we do know some things. We know galaxies are very far away, so far it's taken their light billions of years to reach us (so long, Creationism). We also know that they interact with each other, but we've no idea just how important this is. The current line of thinking is that virtually everything can be explained by mergers, but this actually has so many problems I really don't know where to start. That could be a whole other post, at some point.

We are also dead certain that they are pretty.

Another thing we know is that galaxies have different properties depending on how far away they are (which on these scales is the same as how old they are), but it really doesn't matter where they are on in the sky. That's another nail in the coffin for the steady state theory, where nothing much should change over time.

I won't go into details of galaxy evolutionary theory, but it's worth pointing out that we have no idea what 90% of galaxies are made of. We know that they're rotating too fast, and should all fly apart without something else there to hold them together, but we haven't a clue what it might be (many ideas yes, but no evidence as yet). It's also possible that our understanding of gravity is wrong.5) The Solar System
The solar system was probably formed around 5 billion years ago, based on models of stellar evolution and radioactive dating. These are independent methods which give pretty much the same result, which is always nice. The existence of elements which continuously decay by radiation is also another problem for poor old steady state theory. A Universe that's infinite in time and space really is quite difficult to justify these days.

But. as with everything else, there are still a lot of unknowns. We definitely do know that solar system formed, because we're here. But we're not even sure about some fundamentals as where the gas giants formed or even how many there were. There are also problems with simulations in forming the rocky planets. Yet for all that. we know there must be a solution, because now we know that planetary systems are common around other stars.

6) Dark Energy
Throw a sheep up into the air and will be very surprised, but it will likely come back down again amd run away. That is, unless you throw it upwards with enough speed to escape the gravitational pull of the Earth. In that case, it won't (which is a shame, because the heat generated by air compression would make for instant roast mutton).

This deserves to be everywhere.

The expansion of the Universe is no different, except that it doesn't go "baaa" and is less woolly. That is, by rights the expansion of the Universe ought to slow down, and then it ought to start contracting. That's because everything has mass, and mass means gravity which tends to pull things together.

Even if the unfortunate sheep were put inside a rocket and shot straight up at escape velocity, the unexpectedly intrepid mammal would find itself forever slowing down once the rocket had exhausted all its fuel. It's just that its speed would drop more and more slowly each day, so, although if you waited long enough, it would slow to a crawl, it would never actually stop. Sort of like Zeno's Paradox, only with rockets and sheep instead of Achilles and a tortoise.

Unfortunately, the expansion of the Universe is not slowing down. It appears to be speeding up.

This is allowed by the Einstein's laws of gravity, which is nice. The problem is that no-one knows what the physical mechanism causing the speedup is. It could be some completely unexpected force, or even just a total illusion. It's probably still too early in the game to tell.

Well, that's all I've got. Of course, everything I've just said is a massive oversimplification, but the links contained therein are much better, Inasmuch as I have any conclusions, I suppose they'd have to be the following :

- Anyone who claims that all of modern science is wrong is... well, wrong.
- Anyone who claims that science can already explain everything and thinks there's no more important work left to do is a f***ing IDIOT. Slap them.

Saturday, 23 February 2013

Some of the greatest discoveries in science have come from crackpots with theories they've obviously thought of while smoking something illegal. Obvious, that is, at the time. With hindsight, X-rays, aeroplanes and rockets seem like very good ideas indeed, but no less an authority than Lord Kelvin poo-poohed X-rays and aeroplanes, while the New York Times decided that rockets couldn't work in space as there'd be nothing to push against.

But the most often-quoted "I told you so" moment concerns Alfred Wegener, who looked at the continents of the Earth and reckoned that they could probably all fit together pretty well. On the face of it, this theory is bloody stupid. Whole continents sailing about the world ? There there Wegener, be a good chap and pass the opium.

Also, he was a vampire.

Of course, he turned out to be dead right. Unfortunately, every crackpot under the sun now uses this to justify their own stupid theories. Much as "Godwins Law" means that anyone trying to draw comparisons to the Nazis instantly looses the argument, so we also need some sort of Wegenerian law to stop lunatics comparing themselves to the genuinely misunderstood Wegener.

Some examples. As as scientist I get fairly regular emails (and occasionally real post) about revolutionary new theories. It's an occupational hazard. The latest is an extremely badly-written and very boring website which can be viewed here. You don't want to though. It's dull. I've no idea if some poor sod has genuinely taken the time to invent a new and pointless theory or if it's just some massively elaborate scamming routine.

Then of course there's the notorious TimeCube, where a very angry man has decided thata) Everyone is evil apart from him andb) Something about days being made up of 4 different days happening simultaneously, or something.
I don't know what he's talking about and no-one else does either.

But my all-time favourite has to be the downright strange Space Mirror Mystery. This very well-designed but badly-worded website espouses the theory that there's a giant mirror, 300 million km wide, surrounding the Earth. Nothing exists further away than this, it's all just reflections in the space mirror (I can think of 7 spacecraft off the top of my head further away than this, but never mind). The best bit is that you can download "items" 1-4 for free, but to get item 5 (whatever that is) you have to pay a very specific $101.

Which is why I want to be a pseudoscientist. Not for them the drudgery of sifting through data, endlessly analysing and re-analysing in the hope of making an iota of progress. They don't have to toil away, re-writing the same damn thing over and over again in different ways, or give Power Point presentations to anyone, or have to worry how much it will cost them to publish a paper with colour figures. No, for them it's much easier to claim that it's all bollocks and blame it on the Moon*, or Nazi space werewolves or whatever.

* In the case of astrologers I mean this literally.

This sounds a lot more fun to me. Screw astronomy. I think I'll be the world's first radio astrologer. Sure, we know all about planetary influences, but what about distant quasars ? If Jupiter rising in Scorpios can cause you to feel slightly put-out for a few days, what happens when the Crab pulsar is directly overhead ? Does it make your natural sense of timing much much better ? Does a very bright continuum source cause you to feel all wibbly ? What about when an GPS satellite - which is much brighter than any natural sources - moves through your star sign ?The last one is obvious - the US government is bent on using the mystical energies of GPS satellites to control the destiny of everyone on Earth. Hell, those jerks are probably using ley lines as well.EDIT : I drafted this a while ago but it slipped off the front page and I forgot to publish it. Alas, the "space mirror mystery" website no longer functions, so I replaced the link in the text with a webarhive version - fortunately this contains about 90% of the original material.

Sunday, 17 February 2013

A while back I reported that you can now buy selected renderings via StockTrek images, which has resulted in me dredging up some very old files and dragging them kicking and screaming into whatever decade we call this (the tens ? the twenty-tens ? the twenty-teens ?). While off galivanting around the UK over Christmas I managed to retrieve some missing files from the almost archaic media of CDs (these files are so old that even CD-writers were pretty new and fancy for home tech at the time).

Last time the re-rendering amounted to little more than some basic texturing and lighting adjustments, which is simple enough. That was also the case for Scorpion-class attack cruiser :

Original render (top) and shiny new version (bottom).

The warship dates back to April 2004 and was made for a contest at Scifi-Meshes, taking 4th place. Incidentally it's one of very few absolutely original designs I've made.

The other re-renders are just as old, but were in considerably worse shape. The warship was a single standalone project that took about a month to make, and even back then this allowed for plenty of greebles (small, random details). The satellites from 2001 : A Short Odyssey were made for animation, and although parts of the old models are sufficiently detailed, large parts weren't.

This was driven by two factors : 1) They were part of the classic overly-ambitious crucible of a project that all CG practicioners have to endure, so I didn't want to spend a month on each one; 2) Rendering times had to be kept short with the technology of 2004. Which is not an insignificant difference - multi-core processors were unknown, single-core processors were around the 1 GHz mark, and ray-tracing for free software was pretty much brand spanking new (and so without much in the way of optimisation).

Well, that was then, and this is now. Quad-core processors are the norm, RAM and even GPU memory are measured in gigabytes, ray-tracing has had a decade of refinement, and mesh-modelling tools have improved quite a lot. And, I'd like to think, perhaps I've even learned a thing or two about image composition. For these models, I increased the vertex count by a factor 5-10, so they are essentially entirely new (although some original parts have survived).

The above is apparently the Chinese satellite featured in 2001. In the movie there is a little Chinese logo just about visible, although I didn't bother with it here. The satellites were originally planned to be orbital weapons platforms . There's really no evidence of this in most of their designs though. At worst, the Chinese satellite looks like it might be able to... umm.... gently nudge an enemy ship ? If it was very lucky ?

This one is a German satellite, as evidenced by the German flag and even the Iron Cross. It has some long weapon-like protrusion, although exactly what it is is anyone's guess. I rather liked the look of the original design so I tried to follow it quite closely. I was quite pleased with the way the new model turned out, so I also rendered a short flyby animation. It has a little bit of annoying flickering, which is something I'm still trying to fix.

Then we come to the Franco-Bulgarian satellite (the internet tells me it's French or perhaps Bulgarian, so why not). Reference pictures for this were were confusing. Other people's models give it a quite different appearance to mine but I liked my original interpretation well enough.

And finally we come to the other satellite, the first one in Kubrick's movie, which is apparently American. I think because at the time, I hadn't ready access to such a nice reference picture, my interpretation came out radically different to the original. Never mind. I think this one came out nicely enough, though I didn't both with a wallpaper image. It seems I really went to town on the greebles on this one, with the upper part of the ship being virtually unchanged in the re-render.

I said finally, didn't I ? I lied. I also decided to render a flyby of all four satellites. Actually, this is just a test. I've got this crazy notion running around in my head that I should do something like this but with all of my spaceships, from the last ten years of modelling. So while this one has only rudimentary camera work and lighting, the finished product will be better.

Wednesday, 6 February 2013

Unfortunately I've been writing "poetry" in the AGES observing log again. And that means blog readers will have to suffer my verbal effluence as I ramble incoherently about the problems of satellite-induced RFI and the merits of cats in Coleridge-esque manner.

Pretty pictures will follow shortly to placate those not enamoured of Coleridge spoofs.

The Rhyme of The L3 Satellite

How an Astronomer suffered from interference from a Satellite transmitting in the L3 frequency band, and how the Observatory came to be full of Cats, and the many strange things that befell, and by what means the Astronomer learned to cope with the interference.

Part I

It is an orbiting satellite,And it transmiteth at L3,'By thou cursed and wretched RFI,Wherefore must you lower sensitivity ?

ALFA's cover is opened wide,And I am happily observing,I baked these brownies specially,A feast of which I am deserving.'
I've developed a tendency to bake things. Amongst other things it makes the observing runs a lot more pleasant.

It holds him with its transmitting strength,"There was a ship," quoth he,"Hold off ! Unhand me, satellite, SOON !"Eftsoons his strength dropped he.

It holds him with its RFI,The astronomer sat still,And listens like a three-years' child,The satellite hath its will.

The Astronomer sat on a chair,He cannot but choose to fear,The ruin of his collected data,From the satellite so near.

'The rocket was cheered, the launch-pad cleared,Merrily did it aloft,Above the sky, above the clouds,Above the control-room top.

(A source rose up upon the left,O'er the dish came he!And he shone bright, then on the rightSet below the Observatory.)

Higher and higher every minute,Toward orbit the rocket went around - "The Astronomer here had a pang of fear,For he heard a gong-like sound.
CIMA, the software which controls the telescope, is want to produce many a strange sound when anything happens. A gong indicates something has just finished.

CIMA hath found some errors,Red on the screen were thee,Shaking his head with much regret,The Astronomer preferred to flee.

The Astronomer sat on a chair,He cannot but choose to fear,The ruin of his collected data,From the satellite so near.

But now a new source arose, and it,Was tyrannous and strong:It caused unpleasant Gibbs ringing,But lasted not for long.
Gibbs ringing is caused by very bright sources - basically it just means that the data gets slightly noisier than it should be.

With heavy heart and furrowed brow,As those struck with RFI must know,To fear the signal from their foe,And forward hangs his head,The Astronomer stuck fast, ignored the blast,Of the satellite overhead.[CHRISTMAS INTERMISSION : ROBERT MINCHIN TAKES OVER]

Rhys is awayNo poetry todayProblems with the ALFA rotatorSolved before they affected the dataI must turn on the ALFA againTo observe the slowly-drifting skyAnd all I ask is a big dishAnd a star to steer it by